crontab problem

sueco · 08-29-2012, 08:39 AM

Hi

Background to my problem, is that I have done some program that reads some stuff from the internet and puts it into some database.

Problem:I wanted to run the code every 4th hour (0,4,8,12,16,20) so I started crontab with

Code:

00 0,4,8,12,16,20 * * * java -jar /home/xxxxx/CODE/Database/database.jar

but some weird behavior appears, sometimes it works and sometimes it doesn't. as you can see in the print from the database below

Code:

| 15 |        8 |        16 | 2012-08-26 00:00:10 |
| 16 |       11 |        15 | 2012-08-26 16:00:08 |
| 17 |       10 |        15 | 2012-08-26 20:00:07 |
| 18 |        4 |        17 | 2012-08-27 08:00:04 |
| 19 |       10 |        20 | 2012-08-27 12:00:16 |
| 20 |       13 |        14 | 2012-08-27 16:00:05 |
| 21 |        6 |        14 | 2012-08-28 04:00:04 |
| 22 |        5 |        18 | 2012-08-28 08:00:04 |
| 23 |       10 |        18 | 2012-08-28 12:00:07 |
| 24 |       14 |        16 | 2012-08-28 16:00:11 |
| 25 |       11 |        20 | 2012-08-29 08:00:05 |
+----+----------+-----------+---------------------+

My computer is allways on and connected to the internet. So I don't understand why it works randomly. Have I missed something?

lleb · 08-29-2012, 08:44 AM

does not look like you are missing anything, but you can check /var/log/cron to see if it is starting as scheduled. if it is, then it is not cron.

just FYI an easier way to set the cron to run every 4hrs would be:

Code:

00      */4    *     *     *    foo

sueco · 08-29-2012, 09:27 AM

Hi.

I can't even find anything that got the name of cron in "/var/log/"
Can it be somewhere else?

earthnet · 08-29-2012, 10:38 AM

On my system cron logs to /var/log/messages.

lleb · 08-29-2012, 11:34 AM

try here maybe this will help with ubuntu logs for cron:

http://askubuntu.com/questions/56683...on-crontab-log

good luck.